Zend zend_qsort problem

Anon

I have the C-problem, while compiling php4 latest + AIX 4.3.3 .Following errot is thrown after "make"

"zend_qsort.c", line 33.18: 1506-025 (S) Operand must be a
modifiable lvalue.
"zend_qsort.c", line 34.18: 1506-025 (S) Operand must be a
modifiable lvalue.
"zend_qsort.c", line 39.18: 1506-025 (S) Operand must be a
modifiable lvalue.
"zend_qsort.c", line 40.18: 1506-025 (S) Operand must be a
modifiable lvalue.
make: 1254-004 The error code from the last command is 1.

Here is the source lines :

line 34 is :

((int )a)++ = (int )b;

I removed the ++ sign to successfully compile, but it is not the right way. I think it is possible to write this expression another way . But how.
thanks

static void _zend_qsort_swap(void a, void b, size_t siz)

{
register size_t i;
register int t_i;
register char t_c;
    for (i = sizeof(int); i <= siz; i += sizeof(int)) {
            t_i = *(int *) a;
            *((int *) a)++ = *(int *) 
b; <-

((int ) b)++ =
t_i; <-
}
    for (i = i - sizeof(int) + 1; i <= siz; ++i) {
            t_c = *(char *) a;
            *((char *) a)++ = *(char *) 
b; -<<<<
((char ) b)++ =
t_c; <- riadok 40
}
}